* [RFC] Fix restore from hibernate with different kernel versions.
@ 2013-05-02 1:53 Konrad Rzeszutek Wilk
2013-05-02 1:53 ` [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path Konrad Rzeszutek Wilk
0 siblings, 1 reply; 5+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-05-02 1:53 UTC (permalink / raw)
To: linux-kernel, linux-pm, rjw, pavel, tglx, mingo, hpa, x86
This patch is intended for v3.10 and it should be considered RFC as I had
only tested it under QEMU and not real hardware (that to be done on Friday).
The patch addresses a shortcomming of the git commite
7a5cd063c7b4c58417f674821d63f5eb6747e37 ("x86-64, gdt: Store/load GDT for
ACPI S3 or hibernate/resume path is not needed.") where its assumption
about restoring a kernel was incorrect. Specifically it assumed that a resumed
kernel MUST be the same as the one booted. That is only true for 32-bit
kernels but not for 64-bit.
And as such it introduces a regression which the attached patch is
fixing.
The patch goes further and also lays the groundwork to make this work under
a 32-bit kernel - even though it is not neccessary. This is done to unify
the 32 and 64-bit code and make it easier in the future to unify the
respective code closer.
arch/x86/include/asm/suspend_32.h | 1 +
arch/x86/include/asm/suspend_64.h | 2 ++
arch/x86/kernel/asm-offsets_32.c | 3 +++
arch/x86/kernel/asm-offsets_64.c | 1 +
arch/x86/power/cpu.c | 15 ++++++++++-----
arch/x86/power/hibernate_asm_32.S | 4 ++++
arch/x86/power/hibernate_asm_64.S | 3 +++
7 files changed, 24 insertions(+), 5 deletions(-)
Konrad Rzeszutek Wilk (1):
x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path.
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path. 2013-05-02 1:53 [RFC] Fix restore from hibernate with different kernel versions Konrad Rzeszutek Wilk @ 2013-05-02 1:53 ` Konrad Rzeszutek Wilk 2013-05-02 12:00 ` Rafael J. Wysocki 2013-05-02 12:34 ` Pavel Machek 0 siblings, 2 replies; 5+ messages in thread From: Konrad Rzeszutek Wilk @ 2013-05-02 1:53 UTC (permalink / raw) To: linux-kernel, linux-pm, rjw, pavel, tglx, mingo, hpa, x86 Cc: Konrad Rzeszutek Wilk The git commite7a5cd063c7b4c58417f674821d63f5eb6747e37 ("x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path is not needed.") assumes that for the hibernate path the booting kernel and the resuming kernel MUST be the same. That is certainly the case for a 32-bit kernel (see check_image_kernel and CONFIG_ARCH_HIBERNATION_HEADER config option). However for 64-bit kernels it is OK to have a different kernel version (and size of the image) of the booting and resuming kernels. Hence the above mentioned git commit introduces an regression. This patch fixes it by introducing a 'struct desc_ptr gdt_desc' back in the 'struct saved_context'. However instead of having in the 'save_processor_state' and 'restore_processor_state' the store/load_gdt calls, we are only saving the GDT in the save_processor_state. For the restore path the lgdt operation is done in hibernate_asm_[32|64].S in the 'restore_registers' path. The apt reader of this description will recognize that only 64-bit kernels need this treatment, not 32-bit. This patch adds the logic in the 32-bit path to be more similar to 64-bit so that in the future the unification process can take advantage of this. Suggested-by: "H. Peter Anvin" <hpa@zytor.com> CC: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- arch/x86/include/asm/suspend_32.h | 1 + arch/x86/include/asm/suspend_64.h | 2 ++ arch/x86/kernel/asm-offsets_32.c | 3 +++ arch/x86/kernel/asm-offsets_64.c | 1 + arch/x86/power/cpu.c | 15 ++++++++++----- arch/x86/power/hibernate_asm_32.S | 4 ++++ arch/x86/power/hibernate_asm_64.S | 3 +++ 7 files changed, 24 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/suspend_32.h b/arch/x86/include/asm/suspend_32.h index f6064b7..552d6c9 100644 --- a/arch/x86/include/asm/suspend_32.h +++ b/arch/x86/include/asm/suspend_32.h @@ -15,6 +15,7 @@ struct saved_context { unsigned long cr0, cr2, cr3, cr4; u64 misc_enable; bool misc_enable_saved; + struct desc_ptr gdt_desc; struct desc_ptr idt; u16 ldt; u16 tss; diff --git a/arch/x86/include/asm/suspend_64.h b/arch/x86/include/asm/suspend_64.h index 97b84e0..bc62328 100644 --- a/arch/x86/include/asm/suspend_64.h +++ b/arch/x86/include/asm/suspend_64.h @@ -25,6 +25,8 @@ struct saved_context { u64 misc_enable; bool misc_enable_saved; unsigned long efer; + u16 gdt_pad; /* Unused */ + struct desc_ptr gdt_desc; u16 idt_pad; u16 idt_limit; unsigned long idt_base; diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c index 85d98ab..0ef4bba 100644 --- a/arch/x86/kernel/asm-offsets_32.c +++ b/arch/x86/kernel/asm-offsets_32.c @@ -60,6 +60,9 @@ void foo(void) OFFSET(IA32_RT_SIGFRAME_sigcontext, rt_sigframe, uc.uc_mcontext); BLANK(); + OFFSET(saved_context_gdt_desc, saved_context, gdt_desc); + BLANK(); + /* Offset from the sysenter stack to tss.sp0 */ DEFINE(TSS_sysenter_sp0, offsetof(struct tss_struct, x86_tss.sp0) - sizeof(struct tss_struct)); diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c index 1b4754f..e7c798b 100644 --- a/arch/x86/kernel/asm-offsets_64.c +++ b/arch/x86/kernel/asm-offsets_64.c @@ -73,6 +73,7 @@ int main(void) ENTRY(cr3); ENTRY(cr4); ENTRY(cr8); + ENTRY(gdt_desc); BLANK(); #undef ENTRY diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 6d6e907..1cf5b30 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -25,16 +25,12 @@ #include <asm/cpu.h> #ifdef CONFIG_X86_32 -static struct saved_context saved_context; - unsigned long saved_context_ebx; unsigned long saved_context_esp, saved_context_ebp; unsigned long saved_context_esi, saved_context_edi; unsigned long saved_context_eflags; -#else -/* CONFIG_X86_64 */ -struct saved_context saved_context; #endif +struct saved_context saved_context; /** * __save_processor_state - save CPU registers before creating a @@ -67,6 +63,15 @@ static void __save_processor_state(struct saved_context *ctxt) /* CONFIG_X86_64 */ store_idt((struct desc_ptr *)&ctxt->idt_limit); #endif + /* + * We save it here, but restore it only in the hibernate case. + * For ACPI S3 resume, this is loaded via 'early_gdt_desc' in 64-bit + * mode in "secondary_startup_64". In 32-bit mode it is done via + * 'pmode_gdt' in wakeup_start. + */ + ctxt->gdt_desc.size = GDT_SIZE - 1; + ctxt->gdt_desc.address = (unsigned long)get_cpu_gdt_table(smp_processor_id()); + store_tr(ctxt->tr); /* XMM0..XMM15 should be handled by kernel_fpu_begin(). */ diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S index ad47dae..1d0fa0e 100644 --- a/arch/x86/power/hibernate_asm_32.S +++ b/arch/x86/power/hibernate_asm_32.S @@ -75,6 +75,10 @@ done: pushl saved_context_eflags popfl + /* Saved in save_processor_state. */ + movl $saved_context, %eax + lgdt saved_context_gdt_desc(%eax) + xorl %eax, %eax ret diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S index 9356547..3c4469a 100644 --- a/arch/x86/power/hibernate_asm_64.S +++ b/arch/x86/power/hibernate_asm_64.S @@ -139,6 +139,9 @@ ENTRY(restore_registers) pushq pt_regs_flags(%rax) popfq + /* Saved in save_processor_state. */ + lgdt saved_context_gdt_desc(%rax) + xorq %rax, %rax /* tell the hibernation core that we've just restored the memory */ -- 1.8.1.4 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path. 2013-05-02 1:53 ` [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path Konrad Rzeszutek Wilk @ 2013-05-02 12:00 ` Rafael J. Wysocki 2013-05-02 12:34 ` Pavel Machek 1 sibling, 0 replies; 5+ messages in thread From: Rafael J. Wysocki @ 2013-05-02 12:00 UTC (permalink / raw) To: Konrad Rzeszutek Wilk Cc: linux-kernel, linux-pm, pavel, tglx, mingo, hpa, x86 On Wednesday, May 01, 2013 09:53:30 PM Konrad Rzeszutek Wilk wrote: > The git commite7a5cd063c7b4c58417f674821d63f5eb6747e37 > ("x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path > is not needed.") assumes that for the hibernate path the booting > kernel and the resuming kernel MUST be the same. That is certainly > the case for a 32-bit kernel (see check_image_kernel and > CONFIG_ARCH_HIBERNATION_HEADER config option). > > However for 64-bit kernels it is OK to have a different kernel > version (and size of the image) of the booting and resuming kernels. > Hence the above mentioned git commit introduces an regression. > > This patch fixes it by introducing a 'struct desc_ptr gdt_desc' > back in the 'struct saved_context'. However instead of having in the > 'save_processor_state' and 'restore_processor_state' the > store/load_gdt calls, we are only saving the GDT in the > save_processor_state. > > For the restore path the lgdt operation is done in > hibernate_asm_[32|64].S in the 'restore_registers' path. > > The apt reader of this description will recognize that only 64-bit > kernels need this treatment, not 32-bit. This patch adds the logic > in the 32-bit path to be more similar to 64-bit so that in the future > the unification process can take advantage of this. > > Suggested-by: "H. Peter Anvin" <hpa@zytor.com> > CC: "Rafael J. Wysocki" <rjw@sisk.pl> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > arch/x86/include/asm/suspend_32.h | 1 + > arch/x86/include/asm/suspend_64.h | 2 ++ > arch/x86/kernel/asm-offsets_32.c | 3 +++ > arch/x86/kernel/asm-offsets_64.c | 1 + > arch/x86/power/cpu.c | 15 ++++++++++----- > arch/x86/power/hibernate_asm_32.S | 4 ++++ > arch/x86/power/hibernate_asm_64.S | 3 +++ > 7 files changed, 24 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/include/asm/suspend_32.h b/arch/x86/include/asm/suspend_32.h > index f6064b7..552d6c9 100644 > --- a/arch/x86/include/asm/suspend_32.h > +++ b/arch/x86/include/asm/suspend_32.h > @@ -15,6 +15,7 @@ struct saved_context { > unsigned long cr0, cr2, cr3, cr4; > u64 misc_enable; > bool misc_enable_saved; > + struct desc_ptr gdt_desc; > struct desc_ptr idt; > u16 ldt; > u16 tss; > diff --git a/arch/x86/include/asm/suspend_64.h b/arch/x86/include/asm/suspend_64.h > index 97b84e0..bc62328 100644 > --- a/arch/x86/include/asm/suspend_64.h > +++ b/arch/x86/include/asm/suspend_64.h > @@ -25,6 +25,8 @@ struct saved_context { > u64 misc_enable; > bool misc_enable_saved; > unsigned long efer; > + u16 gdt_pad; /* Unused */ > + struct desc_ptr gdt_desc; > u16 idt_pad; > u16 idt_limit; > unsigned long idt_base; > diff --git a/arch/x86/kernel/asm-offsets_32.c b/arch/x86/kernel/asm-offsets_32.c > index 85d98ab..0ef4bba 100644 > --- a/arch/x86/kernel/asm-offsets_32.c > +++ b/arch/x86/kernel/asm-offsets_32.c > @@ -60,6 +60,9 @@ void foo(void) > OFFSET(IA32_RT_SIGFRAME_sigcontext, rt_sigframe, uc.uc_mcontext); > BLANK(); > > + OFFSET(saved_context_gdt_desc, saved_context, gdt_desc); > + BLANK(); > + > /* Offset from the sysenter stack to tss.sp0 */ > DEFINE(TSS_sysenter_sp0, offsetof(struct tss_struct, x86_tss.sp0) - > sizeof(struct tss_struct)); > diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c > index 1b4754f..e7c798b 100644 > --- a/arch/x86/kernel/asm-offsets_64.c > +++ b/arch/x86/kernel/asm-offsets_64.c > @@ -73,6 +73,7 @@ int main(void) > ENTRY(cr3); > ENTRY(cr4); > ENTRY(cr8); > + ENTRY(gdt_desc); > BLANK(); > #undef ENTRY > > diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c > index 6d6e907..1cf5b30 100644 > --- a/arch/x86/power/cpu.c > +++ b/arch/x86/power/cpu.c > @@ -25,16 +25,12 @@ > #include <asm/cpu.h> > > #ifdef CONFIG_X86_32 > -static struct saved_context saved_context; > - > unsigned long saved_context_ebx; > unsigned long saved_context_esp, saved_context_ebp; > unsigned long saved_context_esi, saved_context_edi; > unsigned long saved_context_eflags; > -#else > -/* CONFIG_X86_64 */ > -struct saved_context saved_context; > #endif > +struct saved_context saved_context; > > /** > * __save_processor_state - save CPU registers before creating a > @@ -67,6 +63,15 @@ static void __save_processor_state(struct saved_context *ctxt) > /* CONFIG_X86_64 */ > store_idt((struct desc_ptr *)&ctxt->idt_limit); > #endif > + /* > + * We save it here, but restore it only in the hibernate case. > + * For ACPI S3 resume, this is loaded via 'early_gdt_desc' in 64-bit > + * mode in "secondary_startup_64". In 32-bit mode it is done via > + * 'pmode_gdt' in wakeup_start. > + */ > + ctxt->gdt_desc.size = GDT_SIZE - 1; > + ctxt->gdt_desc.address = (unsigned long)get_cpu_gdt_table(smp_processor_id()); > + > store_tr(ctxt->tr); > > /* XMM0..XMM15 should be handled by kernel_fpu_begin(). */ > diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S > index ad47dae..1d0fa0e 100644 > --- a/arch/x86/power/hibernate_asm_32.S > +++ b/arch/x86/power/hibernate_asm_32.S > @@ -75,6 +75,10 @@ done: > pushl saved_context_eflags > popfl > > + /* Saved in save_processor_state. */ > + movl $saved_context, %eax > + lgdt saved_context_gdt_desc(%eax) > + > xorl %eax, %eax > > ret > diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S > index 9356547..3c4469a 100644 > --- a/arch/x86/power/hibernate_asm_64.S > +++ b/arch/x86/power/hibernate_asm_64.S > @@ -139,6 +139,9 @@ ENTRY(restore_registers) > pushq pt_regs_flags(%rax) > popfq > > + /* Saved in save_processor_state. */ > + lgdt saved_context_gdt_desc(%rax) > + > xorq %rax, %rax > > /* tell the hibernation core that we've just restored the memory */ > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path. 2013-05-02 1:53 ` [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path Konrad Rzeszutek Wilk 2013-05-02 12:00 ` Rafael J. Wysocki @ 2013-05-02 12:34 ` Pavel Machek 2013-05-02 12:50 ` Konrad Rzeszutek Wilk 1 sibling, 1 reply; 5+ messages in thread From: Pavel Machek @ 2013-05-02 12:34 UTC (permalink / raw) To: Konrad Rzeszutek Wilk; +Cc: linux-kernel, linux-pm, rjw, tglx, mingo, hpa, x86 Hi! > The git commite7a5cd063c7b4c58417f674821d63f5eb6747e37 > ("x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path > is not needed.") assumes that for the hibernate path the booting > kernel and the resuming kernel MUST be the same. That is certainly > the case for a 32-bit kernel (see check_image_kernel and > CONFIG_ARCH_HIBERNATION_HEADER config option). > > However for 64-bit kernels it is OK to have a different kernel > version (and size of the image) of the booting and resuming kernels. > Hence the above mentioned git commit introduces an regression. Ok. > This patch fixes it by introducing a 'struct desc_ptr gdt_desc' > back in the 'struct saved_context'. However instead of having in the > 'save_processor_state' and 'restore_processor_state' the > store/load_gdt calls, we are only saving the GDT in the > save_processor_state. > > For the restore path the lgdt operation is done in > hibernate_asm_[32|64].S in the 'restore_registers' path. So the on-disk format changed and we need to bump the version number somewhere? I guess we should add big fat warning to the affected structures. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path. 2013-05-02 12:34 ` Pavel Machek @ 2013-05-02 12:50 ` Konrad Rzeszutek Wilk 0 siblings, 0 replies; 5+ messages in thread From: Konrad Rzeszutek Wilk @ 2013-05-02 12:50 UTC (permalink / raw) To: Pavel Machek; +Cc: linux-kernel, linux-pm, rjw, tglx, mingo, hpa, x86 On Thu, May 02, 2013 at 02:34:38PM +0200, Pavel Machek wrote: > Hi! > > > The git commite7a5cd063c7b4c58417f674821d63f5eb6747e37 > > ("x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path > > is not needed.") assumes that for the hibernate path the booting > > kernel and the resuming kernel MUST be the same. That is certainly > > the case for a 32-bit kernel (see check_image_kernel and > > CONFIG_ARCH_HIBERNATION_HEADER config option). > > > > However for 64-bit kernels it is OK to have a different kernel > > version (and size of the image) of the booting and resuming kernels. > > Hence the above mentioned git commit introduces an regression. > > Ok. > > > This patch fixes it by introducing a 'struct desc_ptr gdt_desc' > > back in the 'struct saved_context'. However instead of having in the > > 'save_processor_state' and 'restore_processor_state' the > > store/load_gdt calls, we are only saving the GDT in the > > save_processor_state. > > > > For the restore path the lgdt operation is done in > > hibernate_asm_[32|64].S in the 'restore_registers' path. > > So the on-disk format changed and we need to bump the version number > somewhere? Fortunatly not. The patch (7a5cd063c7b4c58417f674821d63f5eb6747e37) that just just landed in Linus a couple of days ago did change it a bit (as the 'saved_context' struct shrunk), but this patch brings it back to what it was before. But I don't know if the 'saved_context' structure is actually somewhere specifically mentioned as 'on-disk' or in the kernel. Looking at the code, I think the on-disk structure you are referring to is the 'struct restore_data_record' (please correct me if I am incorrect) which has not been affected by any of these patches. > > I guess we should add big fat warning to the affected structures. We certainly can. I can prep a patch to that affect on Friday or Monday. > > Pavel > > -- > (english) http://www.livejournal.com/~pavelmachek > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-05-02 12:50 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2013-05-02 1:53 [RFC] Fix restore from hibernate with different kernel versions Konrad Rzeszutek Wilk 2013-05-02 1:53 ` [PATCH] x86, x86-64, gdt, hibernate: Store/load GDT for hibernate path Konrad Rzeszutek Wilk 2013-05-02 12:00 ` Rafael J. Wysocki 2013-05-02 12:34 ` Pavel Machek 2013-05-02 12:50 ` Konrad Rzeszutek Wilk
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).